苦瓜素类似物的分离纯化及其性质研究

本文采用硫酸铵分级沉淀、亲和层析、凝胶过滤等方法,从苦瓜(Momordicacharantia)种仁分得苦瓜素Ⅰ、Ⅱ。它们在SDS-聚丙烯酰胺凝胶电泳和等电聚焦电泳上均呈现单一区带,其分子量分别为26 000和28 000,等电点8.3,含糖量1.6％和2.0％。苦瓜素Ⅰ对小鼠腹腔给药LD_(50)值为2.54mg/kg,苦瓜素Ⅱ的致死剂量范围是9-14mg/kg。它们对无细胞体系蛋白合成都有强烈的抑制活性,其IC_(50)均小于0.1ng/mL。我们将苦瓜素Ⅰ、Ⅱ与文献报道的苦瓜抑制剂(Momordica chanantiainhibitor,MCI)和α、β-momorcharin进行了比较,发现它们分别与MCI和α-momorcharin相似。由于苦瓜素Ⅱ的毒性较低,更适合于制备免疫毒素。

Purification and Characterazation of the Analogues of Mo-morcharin

Momorcharin-******I and *********II was separated from the seeds of Momorcdica char-antia by precipitation at 30-60% saturation of (NH4)2SO4, followed by affinity chromatography on sepharose 4B and sephadex G-75 gel filtration.The results of SDS-PAGE electrophoresis and isoelectric focusing showed that momorcharin-*******I and ********II were homogeneous single bands with pI's of 8.3, molecular weights of 26 000 and 28000, and sugar contents of 1.6% and 2.0% respectively.The LD50 for mice when injected intraperitoneally were 2.54 and 9-14mg/kg respectively.Momorcharin-*******I and ********II were very potent in inhibitions of protein sythesis in the cell-free system and the IC50 were both less than 0.1ng/mL.The inhibition effects on protein synthesis of momorcharin-********I and *******II have been compared with that of the MCI and *********a, ***********b-momorcharin reported in literature and similarities of momorcharin respectively were found.Due to the lower toxicity, momorcharin *******IIn is more suitable for the preparation of immunotoxin.